LD typing in man using cells frozen and stored in microtiter plates

A method of freezing LD typing cells in microtiter plates was developed. Two times 10(5) lymphocytes in a small volume (15 mul) with a low DMSO concentration (5%) were directly frozen in a --70 degrees C freezer. These cells were used in the mixed lymphocyte culture after thawing by diluting step-by-step with serum and culture medium without washing. The kinetics obtained with cells frozen in microtiter plates were comparable to those with fresh cells. Typing for LD determinants was performed in a group of unrelated persons in a family study using the LD homozygous reference cell Pi frozen in microtiter plates.